The invention relates to a device for supplying, centering, and cutting a wire in a stapling device, the subsequent formation of a staple from the wire, and stapling a stack of sheets.
Devices of the type mentioned above for supplying, centering, and cutting a stapling wire in a sheet stack stapling device by means of staple forming are known and are used in duplicating equipment.
DE 197 12 876-A1 discloses a sheet stack stapling device in which individual stapling wire sections are cut from stapling wire supplied from a stapling wire supply, positioned concentrically to a former and driver, formed into a staple, and driven into a stack of sheets and in which an adjustable stapling wire-cutting device is mounted so that it can slide, depending on the thickness of the stack of sheets to be stapled. A swivel-mounted control lever, which is in contact with a cam unit, engages with the cutting device. The cam unit is driven by way of a free wheel clutch, one end of which is connected to the cam unit and can be driven by a stepper motor of a stapling wire supply unit. The other end of the free wheel clutch is in engagement with a transport wheel for the stapling wire transport. The cam unit has cam sections that are assigned to different sheet stack thicknesses.
Depending on the measured sheet stack thickness, the stepper motor turns the cam unit to a setting that brings the cutting device into a position by way of the control lever, in which the wire section length can be cut as assigned to the sheet stack thickness.
In this disclosed sheet stack stapling device, the disadvantage is that the supply of the stapling wire by the length section determined for the sheet stack thickness and the centering of the stapling wire section have to be additionally carried out using control sections of control cams driven by the stepper motor that can be engaged by means of the clutch with the use of an additional stapling wire return lock, and that the positioning of the cutting device also has to be carried out by control cams controlled by the stepper motor, which is complicated in design and costly and critical for functional safety and positioning accuracy. In addition, in the case of a malfunction after the stapling wire has been supplied, in which the length of the stapling wire has to be determined again because of a subsequently modified sheet stack height, the supplied stapling wire can only be transported back by lifting the return lock and by operating the stepper motor in the opposite rotation direction.
DE 197 12 876-A1 is hereby incorporated by reference as if fully set forth herein.